engine: use DashMap for sharing evaluated nodes

Cargo.lock

@@ -1,5 +1,13 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "ahash"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "const-random 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "ansi_term"
 version = "0.11.0"
@@ -42,6 +50,34 @@ dependencies = [
  "vec_map 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "const-random"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "const-random-macro 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.16 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "const-random-macro"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.16 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "dashmap"
+version = "3.11.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ahash 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "getrandom"
 version = "0.1.14"
@@ -66,46 +102,18 @@ version = "0.2.71"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "ppv-lite86"
+name = "num_cpus"
-version = "0.2.8"
+version = "1.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
-name = "rand"
-version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "hermit-abi 0.1.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.71 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
-name = "rand_chacha"
+name = "proc-macro-hack"
-version = "0.2.2"
+version = "0.5.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "ppv-lite86 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "rand_core"
-version = "0.5.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "rand_hc"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
 
 [[package]]
 name = "strsim"
@@ -130,7 +138,7 @@ name = "vatu"
 version = "0.1.0"
 dependencies = [
  "clap 2.33.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "dashmap 3.11.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -163,19 +171,20 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
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-"checksum rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+"checksum proc-macro-hack 0.5.16 (registry+https://github.com/rust-lang/crates.io-index)" = "7e0456befd48169b9f13ef0f0ad46d492cf9d2dbb918bcf38e01eed4ce3ec5e4"
-"checksum rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
-"checksum rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
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Cargo.toml

@@ -6,4 +6,4 @@ edition = "2018"
 
 [dependencies]
 clap = "2.33"
-rand = "0.7"
+dashmap = "3.11"

src/analysis.rs

@@ -4,6 +4,8 @@ use std::fmt;
 use std::hash::{Hash, Hasher};
 use std::sync::{Arc, atomic, mpsc};
 
+use dashmap::DashMap;
+
 use crate::board;
 use crate::engine;
 use crate::notation;
@@ -71,6 +73,8 @@ impl Hash for Node {
     }
 }
 
+pub type NodeEvalMap = Arc<DashMap<Node, f32>>;
+
 /// Analysis parameters.
 #[derive(Clone)]
 pub struct AnalysisParams {
@@ -88,6 +92,7 @@ const MAX_F32: f32 = std::f32::INFINITY;
 pub fn analyze(
     node: &mut Node,
     _args: &AnalysisParams,
+    score_map: &NodeEvalMap,
     working: Arc<atomic::AtomicBool>,
     tx: mpsc::Sender<engine::Cmd>,
     debug: bool,
@@ -102,7 +107,13 @@ pub fn analyze(
         tx.send(engine::Cmd::Log(moves_str)).unwrap();
     }
 
-    let (max_score, best_move) = minimax(node, 0, 2, board::is_white(node.game_state.color));
+    let (max_score, best_move) = minimax(
+        node,
+        0,
+        3,
+        board::is_white(node.game_state.color),
+        &score_map,
+    );
 
     if best_move.is_some() {
         let log_str = format!(
@@ -145,12 +156,21 @@ fn minimax(
     node: &mut Node,
     depth: u32,
     max_depth: u32,
-    maximizing: bool
+    maximizing: bool,
+    score_map: &NodeEvalMap,
 ) -> (f32, Option<rules::Move>) {
+    // If the node has already been analysed before, return its previous evaluation.
+    if let Some(score) = score_map.get(node) {
+        return (*score.value(), None)
+    }
+    // If we reached max depth, evaluate score for this board, store score and stop recursion.
     if depth == max_depth {
         let stats = stats::compute_stats(&node.board, &node.game_state);
-        return (evaluate(&stats), None);
+        let score = evaluate(&stats);
+        score_map.insert(node.clone(), score);
+        return (score, None);
     }
+    // Else, get the minimax score.
     let mut minmax = if maximizing { MIN_F32 } else { MAX_F32 };
     let mut minmax_move = None;
     let moves = rules::get_player_moves(&node.board, &node.game_state, true);
@@ -158,13 +178,13 @@ fn minimax(
         let mut sub_node = node.clone();
         rules::apply_move_to(&mut sub_node.board, &mut sub_node.game_state, &m);
         if maximizing {
-            let (score, _) = minimax(&mut sub_node, depth + 1, max_depth, false);
+            let (score, _) = minimax(&mut sub_node, depth + 1, max_depth, false, score_map);
             if score >= minmax {
                 minmax = score;
                 minmax_move = Some(m);
             }
         } else {
-            let (score, _) = minimax(&mut sub_node, depth + 1, max_depth, true);
+            let (score, _) = minimax(&mut sub_node, depth + 1, max_depth, true, score_map);
             if score <= minmax {
                 minmax = score;
                 minmax_move = Some(m);

src/engine.rs

@@ -6,6 +6,8 @@
 use std::sync::{Arc, atomic, mpsc};
 use std::thread;
 
+use dashmap::DashMap;
+
 use crate::analysis;
 use crate::board;
 use crate::notation;
@@ -19,7 +21,7 @@ pub struct Engine {
     /// Current game state, starting point of further analysis.
     node: analysis::Node,
     /// Store already evaluated nodes with their score.
-    // score_map: Arc<RwLock<HashMap<Node, f32>>>,
+    score_map: Arc<DashMap<analysis::Node, f32>>,
     /// Communication mode.
     mode: Mode,
     /// If true, the engine is currently listening to incoming cmds.
@@ -77,7 +79,7 @@ impl Engine {
         Engine {
             debug: false,
             node: analysis::Node::new(),
-            // score_map: HashMap::with_capacity(2usize.pow(10)),
+            score_map: Arc::new(DashMap::with_capacity(2usize.pow(10))),
             mode: Mode::No,
             listening: false,
             working: Arc::new(atomic::AtomicBool::new(false)),
@@ -179,11 +181,12 @@ impl Engine {
         self.working.store(true, atomic::Ordering::Relaxed);
         let mut node = self.node.clone();
         let args = args.clone();
+        let score_map = self.score_map.clone();
         let working = self.working.clone();
         let tx = match &self.mode { Mode::Uci(_, _, tx) => tx.clone(), _ => return };
         let debug = self.debug;
         thread::spawn(move || {
-            analysis::analyze(&mut node, &args, working, tx, debug);
+            analysis::analyze(&mut node, &args, &score_map, working, tx, debug);
         });
     }
 

src/rules.rs

@@ -220,7 +220,7 @@ pub fn get_castle_move(castle: u8) -> Move {
 /// see if P's king can be taken. Consider a call with true `commit` as
 /// a collection of attacked squares instead of legal move collection.
 pub fn get_player_moves(board: &Board, game_state: &GameState, commit: bool) -> Vec<Move> {
-    let mut moves = vec!();
+    let mut moves = Vec::with_capacity(256);
     for r in 0..8 {
         for f in 0..8 {
             let p = (f, r);